A patent document 1 discloses a known example of automatic transmission control device. This publication discloses that during a shift such as a downshift where a torque transmission capacity from a drive side to a driven side is increased by slip-engagement of a high and low reverse clutch (henceforth referred to as first frictional engagement element), an engagement capacity of a low coast brake (henceforth referred to as second frictional engagement element) connected to the driven side is increased, to apply a reaction force in a direction opposite to a direction of application of an engagement force of the first frictional engagement element, and thereby suppress judder during shifting. In other words, since judder is likely to occur when a shift employing engagement switching is performed under a condition that the engagement force of the first frictional engagement element is relatively high, the distributed force of the first frictional engagement element is reduced by increasing the engagement capacity of the second frictional engagement element connected to the driven side.
However, the increase of the engagement capacity of the second frictional engagement element tends to cause interlocking, and thereby may cause a driving force to fall. Furthermore, the increase of the engagement capacity of the second frictional engagement element causes a necessity to take a countermeasure against judder of the second frictional engagement element.